Electrophotographic imaging members, i.e., photoreceptors, typically include a photoconductive layer formed on an electrically conductive substrate. The photoconductive layer is an insulator in the dark so that electric charges are retained on its surface. Upon exposure to light, the charge is dissipated. A latent image is formed on the photoreceptor by first uniformly depositing electric charges over the surface of the photoconductive layer by one of any suitable means known in the art. The photoconductive layer functions as a charge storage capacitor with charge on its free surface and an equal charge of opposite polarity (the counter charge) on the conductive substrate. A light image is then projected onto the photoconductive layer. On those portions of the photoconductive layer that are exposed to light, the electric charge is conducted through the layer reducing the surface charge. The portions of the surface of the photoconductor not exposed to light retain their surface charge. The quantity of electric charge at any particular area of the photoconductive surface is inversely related to the illumination incident thereon, thus forming an electrostatic latent image.
The photo-induced discharge of the photoconductive layer requires that the layer photogenerate conductive charge and transport this charge through the layer thereby neutralizing the charge on the surface. Two types of photoreceptor structures have been employed: multilayer structures wherein separate layers perform the functions of charge generation and charge transport, respectively, reference, for example, U.S. Pat. Nos. 6,824,940 and 6,787,277, the disclosures of each of which are totally incorporated by reference herein; and single layer structures in which photoconductors perform both charge generation and charge transport functions. These layers are formed on an electrically conductive substrate and may include an optional charge blocking layer and an adhesive layer between the conductive substrate and the photoconductive layer or layers. Additionally, the substrate may comprise a non-conducting mechanical support with a conductive surface. Other layers for providing special functions such as incoherent reflection of laser light, dot patterns for pictorial imaging, or subbing layers to provide chemical sealing and/or a smooth coating surface may also be employed. A typical single layer photoreceptor comprises a photogenerating pigment, a thermoplastic binder, a hole transport material, and an electron transport material.
There are many charge transport materials available for electrophotography, reference for example, U.S. Pat. No. 6,645,686, the disclosure of which is hereby totally incorporated by reference herein. Typical charge transport materials include triarylamines.
Charge transporting triarylamines for electrophotographic photoreceptors can be prepared using the Vilsmeier reaction. The Vilsmeier Reaction (or Vilsmeier-Haack Reaction) allows the formylation of electron-rich arenes. The formylating agent, also known as the Vilsmeier Reagent or Vilsmeier-Haack Reagent, is formed in situ from N,N-dimethylformamide (DMF) and phosphorous oxychloride (POCl3).

Reference, for example, U.S. Pat. Nos. 2,558,285 and 2,437,370, the disclosures of each of which are totally incorporated by reference herein.
The traditional Vilsmeier reaction, when used for the monoformylation of triarylamine molecules, requires a large excess of Vilsmeier Reagent (DMF and POCl3) or a solvent system to dissolve the starting material. Solvent free (neat) systems result in extremely viscous reaction mixtures that lead to safety and manufacturing issues. Vilsmeier Reagent is highly corrosive and presents significant safety hazards due to its exothermic nature. Further, use of Vilsmeier Reagent in excess results in high levels of impurities. When a solvent is used in the Vilsmeier Reaction, the viscosity issues are alleviated only if the solvent is miscible with the Vilsmeier Reagent. Most solvents allow multiple formylated products along with other impurities. Many solvents also interfere with hydrolysis and isolation of the end product.
The disclosures of each of the foregoing U.S. patents are each incorporated by reference herein in their entireties. The appropriate components and process aspects of the each of the foregoing U.S. patents may be selected for the present compositions and processes in embodiments thereof.